|dc.contributor.author||Haynes, Christopher Thomas||
|dc.date.copyright||The copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without the prior written consent of the author||
|dc.identifier.citation||Haynes, C.T. 2014. Simulations of Electron Kinetics in Solar Wind Turbulence. Queen Mary University of London||en_US
|dc.description.abstract||Solar wind plasma is a turbulent medium, with processes that operate on many
scales. Observations below proton scales are rare. Future spacecraft missions will
have the required resolution to make these observations, so theoretical experiments
and simulations at these scales will become increasingly important in order to match
observations to theory. In this thesis, kinetic simulations are used to study electron
dynamics within a turbulent electron-proton plasma.
Firstly in this thesis, a study of the formation of electron temperature anisotropy
due to magnetic reconnection is presented using particle in cell (PIC) simulations of
the turbulent decay of sub-proton scale fluctuations. A fluctuation power spectrum
with approximately power law form down to scales of order the electron gyroradius
is formed. The signatures of collisionless reconnection within the turbulent field are
generally associated with regions of strong parallel electron temperature anisotropy.
Electrons from spatially different locations, can mix at reconnection sites, generating
multi-peaked velocity distribution functions, which could become unstable to further
instabilities. This is evidence of an important role for reconnection in the dissipation
of small scale turbulent fluctuations.
Secondly, a new type of electron scale vortex is discussed, which can spontaneously
form during the simulations of turbulence. These are generated by electrons
in (quasi) trapped orbits, which diamagnetically reduce the local magnetic
field, creating a coherent structure. The properties of these vortices are categorized
and compared to observations of similar structures called “magnetic holes” observed
within the Earth’s plasma sheet.
Finally, we look to understand what dissipation is in a collisionless plasma. We examine
signatures of dissipation in the previous simulations, and in simulations where
electrostatic electron-electron beam modes are generated within the turbulence.||en_US
|dc.description.sponsorship||Science and Technology Facilities Council||en_US
|dc.publisher||Queen Mary University of London||en_US
|dc.title||Simulations of Electron Kinetics in Solar Wind Turbulence||en_US